Apr 5 2005
Africa may fail to benefit from new and better drugs for malaria because of massive misdiagnosis of the disease by health workers and patients.
Misdiagnosis sounds like a technical matter. But the implications are far-reaching.
“Because of the rising cost of drugs, the level of misdiagnosis – treating all fevers as malaria - is so high that it is unsustainable,” says Dr Guy Barnish of the Malaria Knowledge Programme at the Liverpool School of Tropical Medicine.
Most Africans – about 80 per cent – who have a fever do not go to a clinic or a doctor: they treat themselves with an anti-malarial drug. But their fever may be caused by a different illness. Buying malaria drugs when you don’t have malaria means that the real illness goes untreated and drug resistance increases. It is also a waste of money.
Liverpool School researchers describe misdiagnosis as “shockingly high” in some areas, with three-quarters of patients complaining of fever advised to take anti-malarial drugs for a non-malarial illness.
Buying the wrong drugs makes poor people poorer still and locks them more tightly, in the words of Dr Barnish and his colleagues, “into a vicious cycle of increasing ill-health and deepening poverty”.
Even if they take their fever to a clinic, malaria is often diagnosed without a blood test and anti-malarial drugs will be prescribed.
Since the new generation of malaria drugs – which are being introduced as the malaria parasite develops resistance - cost more than old-style drugs, this wasteful expenditure of millions of dollars a year will continue to rise.
The only way to halt it is to provide drugs only for people with malaria. And the best way of making a correct diagnosis is by taking blood and examining it under a microscope - “the gold standard method”, according to Barnish.
But are laboratories in Africa efficient enough to do the tests accurately, cheaply, safely and rapidly? The Liverpool School decided to find out.
In some district hospitals in southern Africa researchers found lab conditions that were cramped and unsafe, procedures for cleaning and waste disposal that needed tightening up and lack of essential supplies and spare parts. Another study found unsupervised ancillary staff using microscopes that couldn’t focus and had fungal growth on the lenses.
Sometimes the microscopes were in such a state of disrepair that it was impossible to confirm the presence of malaria parasites on the slides under scrutiny. When laboratory services are so neglected it is not surprising that one study showed that less than half of the results provided by a lab over a six-month period were correct.
Researchers also found that because staff in some laboratories had to take so many days off for family crises, funerals and ill-health – largely as a result of HIV/AIDS – that technicians were not able to spend enough time analysing specimens. (One of the many effects of the pandemic is that it has put such a burden on healthcare services in Africa that laboratories are increasingly unable to deliver quality output.)
Clearly, improvements are needed. Two of the School’s projects have shown it can be done.
Working with Ghanaian researchers, the Liverpool School put microscopes under the microscope. They replaced four of the instruments at a teaching hospital in Kumasi, Ghana, and allocated each of them to an individual technician who was given responsibility for its care and maintenance.
The result: two minutes were cut from the time taken to examine each slide, the number of slides examined rose by up to 50 per cent, and equipment was clean and well cared for. The new instruments paid for themselves in four years.
Since then, the Malaria Knowledge Team has run programmes in Ghana and Malawi that have shown it is possible to set up local and national systems to improve the accuracy of lab tests.
In addition, it has produced a practical model for examining the efficiency of methods of testing for anaemia – the most commonly performed test worldwide. Malawi’s Ministry of Health and Population says it will use the findings to develop a quality-assured district laboratory service.
Keeping microscopes clean, cutting seconds off the time taken to analyse a blood sample, ensuring that spares for laboratory equipment are easy to obtain: such routine tasks are not as dramatic as new drugs or childhood vaccines, but Malawi has indicated that haemoglobin (anaemia) measurement is a key component of essential laboratory services, which themselves form part of the government’s Poverty Reduction Strategy.
That judgment needs to be taken up by others, internationally as well as nationally. As the British Medical Journal said last year: “The international effort that is being put into new malaria drugs should be paralleled by a commitment to improve the availability of accurate diagnostic tools for malaria, so that drugs can be targeted to people with definite malarial illness.”
By Daniel Nelson